Guirao A, Redondo M, Artal P
Laboratorio de Optica, Universidad de Murcia, Spain.
J Opt Soc Am A Opt Image Sci Vis. 2000 Oct;17(10):1697-702. doi: 10.1364/josaa.17.001697.
We investigated how the optical aberrations associated with the anterior surface of the human cornea change with age in a normal population. Aberrations were computed for a central part of the cornea (4, 5, and 6 mm in diameter) from the elevation data provided by a videokeratographic system. Measurements were obtained in 59 normal healthy, near-emmetropic [spherical equivalent lower than 2 diopters (D)] subjects of three age ranges: younger (20-30 years old), middle-aged (40-50 years old), and older (60-70 years old). The average corneal radius decreased with age and the cornea became more spherical. As a consequence, spherical aberration was significantly larger in the middle-aged and older corneas. Coma and other higher-order aberrations also were correlated with age. The root mean square of the wave aberration exhibited a linear positive correlation (P < 0.003) with age for the three ranges of pupil diameter. Despite a large intersubject variability, the average amount of aberration in the human cornea tends to increase moderately with age. However, this increase alone is not enough to explain the substantial reduction previously found in retinal image quality with age. The change in the aberrations of the lens with age and the possible loss of part of the balance between corneal and lenticular aberrations in youth may be the main factors responsible for the reduction of retinal image quality through the life span.
我们研究了在正常人群中，与人类角膜前表面相关的光学像差如何随年龄变化。根据视频角膜地形图系统提供的高度数据，计算角膜中央部分（直径4、5和6毫米）的像差。对59名正常健康、近视性屈光不正（球镜等效度低于2屈光度）的受试者进行了测量，受试者分为三个年龄组：年轻组（20 - 30岁）、中年组（40 - 50岁）和老年组（60 - 70岁）。角膜平均半径随年龄减小，角膜变得更趋近于球形。因此，中年和老年角膜的球差明显更大。彗差和其他高阶像差也与年龄相关。在三个瞳孔直径范围内，波前像差的均方根与年龄呈线性正相关（P < 0.003）。尽管个体间差异很大，但人眼角膜像差的平均量倾向于随年龄适度增加。然而，仅这一增加不足以解释先前发现的视网膜图像质量随年龄大幅下降的现象。晶状体像差随年龄的变化以及年轻时角膜和晶状体像差之间部分平衡可能的丧失，可能是导致一生中视网膜图像质量下降的主要因素。
